UGH I guess one of the reasons is because we are lied to as well by alcoholism and in denial, at least I know I really believed XABF was a good person that alcohol changed!! really hard not to feel bad remembering the good times. You are missing the person he used to be, or showed himself to be once... that's all.
I suffered a lot thinking the "good" Jekyll was wandering around in love with someone else but I am more and more convinced that Jekyll has been lost in the ether and the guy around is someone very very different... and I want nothing to do with that manipulative cruel person. Wow leaving an active alcoholic was the hardest thing I ever did in my short life!! but you will make it... these are the worse moments, when its so fresh... cry all you need and post all you need.......
Try to think about any future kids you may plan to have, and how different their life will be if you stay brave, having a real dad not a ridiculous excuse of a man around to turn everyone's lives to endless torture, sadness etc.
Letting go now is painful but now when I clinge to something or the memory or whatever... I try to relax my body and think "how does it feel to let go?" now it feels peaceful and relaxing. All the best ((KP))